Did God bury alive all of Korah's children?

Yes, God buried them alive.

So they gat up from the tabernacle of Korah, Dathan, and Abiram ... and stood in the door of their tents,
and their wives, and their sons, and their little children.... And the earth opened her mouth, and swallowed them up, and their houses,
and all the men that appertained unto Korah, and all their goods. They, and all that appertained to them, went down alive into the pit,
and the earth closed upon them: and they perished from among the congregation. Numbers 16:27-33